Waves in a Venus general circulation model

Abstract

Waves in the Venus atmosphere are numerically investigated by extending a work of Sugimoto et al. (2014). Fast superrotating zonal flow of 120 m s^-1 at the equator is reproduced and maintained by solar heating for more than 10 Earth years. The meridional distribution of the obtained fast zonal flow is quite consistent with observations at the cloud levels. In the cloud layer, baroclinic waves develop continuously with a life cycle of ~25 Earth days at midlatitudes, using available potential energy derived from a baroclinically unstable basic state. Rossby waves observed at the cloud top are generated by the baroclinic waves and induce spatio-temporal variation of the superrotation with amplitude larger than 25 m s^-1. Further, Kelvin waves with a period of ∼ 6.2 days appear in the equatorial region below ~50 km. Momentum and heat transports produced by these waves are discussed.